Hand-held exercise devices are well known in the art, the best known of which is the hand-held dumbbell. The components of a hand-held dumbbell include a metal bar, a sleeve, two lockable collars and, if desired, plate weights. Typically, the metal bar is about one inch in diameter and about eight to twelve inches in length. The sleeve is formed of a chrome-plated metal and is slid onto the metal bar and positioned in the general center thereof. Oftentimes, the sleeve is knurled to enhance the ability to grip in use. The collars, which are commonly formed from either metal or plastic, are slid over the metal bar, one from each end thereof, and locked into place upon contacting the sleeve, thereby fixedly securing the sleeve in the general center of the metal bar. One or more plate weights may then be slid onto respective ends of the bar such that a generally identical weight is positioned on each end of the sleeve. If plate weights are used with the dumbbell, two additional lockable collars are then slid over respective ends of the metal bar and locked to fixedly secure the plate weights in place. In normal use, a pair of hand-held dumbbells of generally identical weight are held, one in each hand and a variety of exercise routines are performed. While various improvements in hand-held dumbbell design have been made over the years, for example, the development of single piece cast iron or steel hand-held dumbbells and/or vinyl coated hand-held dumbbells, the basic design of the hand-held dumbbell has remained unchanged over the years.
When used in exercise routines, the predominant bio-mechanical characteristic of a traditionally configured hand-held dumbbell is that, once grasped by the hand, the center of gravity of the hand-held dumbbell is in the middle or center of the fist. Furthermore, the moment arm of resistance derived from a traditionally configured hand-held dumbbell is the distance from the center of gravity to the articulation point of the wrist, a distance typically on the order of about three inches. When used in an exercise routine, the hand-held dumbbell has no significant moment arm variations. Accordingly, the use of a traditionally configured hand-held dumbbell may be characterized as an isometrically fixed hand-wrist position hereinafter referred to as a “dead-hand” position. Although wrist-extension and wrist-flexion exercises may be performed using a traditionally configured hand-held dumbbell, they are typically performed by stabilizing the forearms on the thighs or on a so-called “preacher's bench” during the exercise routine. Similarly, while exercise routines involving torque or rotational hand-wrist movements are possible using a traditionally configured hand-held dumbbell, such movements are only possible because generally equal weights are secured on opposite sides of the gripping sleeve, a placement which, in effect, results in an equal amount of weight on each side of the center of gravity. As a result, the torque resistance is essentially zero and, once established, rotational momentum tends to stimulate hand-wrist rotational movement. Because of this, traditionally configured hand-held dumbbells are rarely used to perform rotary exercises routines since they are largely ineffective in producing rotary muscle mass and strength gains.
For the foregoing reasons, the traditionally configured hand-held dumbbell is not particularly useful in any number of exercise routines. It should be readily appreciated, therefore, that it would be advantageous to provide a hand-held exercise device suitable for those exercise routines for which the traditionally configured hand-held dumbbell has proven deficient.